High precision 142Ce/140Ce stable isotope measurements of purified materials with a focus on CeO2 nanoparticles

Abstract

Engineered CeO₂ nanoparticles (NPs) are becoming increasingly prevalent in consumer products and this has raised concerns about the unknown behaviour and fate of such materials in the environment. Analytical limitations have hampered the detection of CeO₂ NPs in natural systems at environmentally relevant levels. This study presents data on the inherent stable isotope composition of commercially available purified Ce materials with a particular focus on CeO₂ NPs. The aim of this investigation is to determine whether CeO₂ NPs posses a distinct isotopic signature that may be exploited for their detection in natural systems. To achieve this, suitable stable isotope measurement protocols were developed for the precise determination of the ¹⁴²Ce/¹⁴⁰Ce isotope ratio by multiple collector ICP-MS using Ba for external normalisation of the instrumental mass bias. The data presented show that precisions of ±0.01‰ (2se) and ±0.04‰ (2sd) can be routinely achieved with these techniques. The results also demonstrate that commercially available CeO₂ NPs do not have a distinct Ce isotope composition that may be exploited for the purpose of stable isotope tracing.